C / C++ / MFC

LighthouseJ6-Oct-05 18:56

6-Oct-05 18:56

See, I have code like this:

if (first test statement) {<br />
(update data)<br />
(invalidate one rectangle)<br />
}<br />
<br />
if (second test statement) {<br />
(update other data)<br />
(invalidate another rectangle)<br />
}

and both sections work independantly as far as what it tests for. The first if statement is run several times more than the second, but I let my program run and something I didn't expect to happens. What happens is that the screen is updated whenever the second statement is run (less often), but both the first and second rectangle are refreshed (with erases). I tried switching the order of the if statements but it still refreshes at the frequency of the lesser used if statement rectangle invalidation. I don't know what to do about it, right now at least.

Jose Lamas Rios6-Oct-05 19:02

6-Oct-05 19:02

I'm not sure I understood your problem, but keep in mind that invalidating just means that it will be updated in then next paint cycle. If you want to make sure the window gets updated after each 'invalidate' you should also call UpdateWindow right after calling InvalidateRect

--
jlr
http://jlamas.blogspot.com/[^]

LighthouseJ6-Oct-05 19:37

6-Oct-05 19:37

I tried that by doing something like this:

bool bUpdateWindow = false;<br />
CWnd * pParent = ::AfxGetMainWnd();<br />
<br />
if (first test) {<br />
(change data)<br />
pParent->InvalidateRect(pRect1, true);<br />
bUpdateWindow = true;<br />
}<br />
<br />
if (second test) {<br />
(change other data)<br />
pParent->InvalidateRect(pRect2, true);<br />
bUpdateWindow = true;<br />
}<br />
<br />
if (bUpdateWindow) { pParent->UpdateWindow(); }

But the behavior isn't changed from before.

Jose Lamas Rios6-Oct-05 19:46

6-Oct-05 19:46

Are you sure it's AfxGetMainWnd() the window you need to invalidate? What kind of window is the main one? Is it a dialog, MDI/SDI frame, or something else?

--
jlr
http://jlamas.blogspot.com/[^]

LighthouseJ6-Oct-05 19:55

6-Oct-05 19:55

hmm, well I'm invalidating and updating the window in a thread... you raise an interesting question. The main window, in the file mainfrm.cpp, is CMainFrame, derived from CFrameWnd. Am I calling it's routines instead of the child and that's what's not right?

Jose Lamas Rios6-Oct-05 20:01

6-Oct-05 20:01

I don't think invalidating CMainFrame would work, because it's unlikely CMainFrame is drawing something based on the data you change. You should be invalidating the specific window that needs to be updated. Better yet, if that's a CView-derived window, you should put the data in a document, modify the data using a document member function, which should call UpdateAllViews. Your view, in its OnUpdate member should invalidate and update itself based on that notification.

--
jlr
http://jlamas.blogspot.com/[^]

LighthouseJ6-Oct-05 20:16

6-Oct-05 20:16

I'm trying to figure out a way to pass the instruction through from thread->CMainFrame(derived from CFrameWnd)->CChildView(derived from CWnd). There's no CView-derived thing in my project. I tried creating a message to pass but that's not working and I tried creating a function in CMainFrame to update the child view when it's called so the thread can call that, but it gives me access violations and it has question marks next to the values for the different window handles. I'm still checking it out.

Jose Lamas Rios7-Oct-05 3:28

7-Oct-05 3:28

If you are in a worker thread you can't make direct calls to CWnd objects created in the main (GUI) thread. Instead, you need to pass a window handle (HWND) to the thread function and use it there to send or post private messages (WM_USER + n) from the worker thread to that window.

--
jlr
http://jlamas.blogspot.com/[^]

LighthouseJ7-Oct-05 4:15

7-Oct-05 4:15

This thread is a user-interface thread, I overrode CWinThread and pass the runtime class name to AfxBeginThread just as the documentation say you're supposed to do for a user-interface thread. I was trying to figure out a way to use messages but maybe I don't know as much as I need to.

I defined a message like:

#define WM_UPDATECHILD (WM_APP + 1)

And tried to create a handler function for that message but it would never be run. I tried to override PreTranslateMessage, OnCmdMsg, and OnCommand to intercept this message, handle it, then return a nonzero result to show it was handled and none of this worked. I just don't know what to do.

What's wrong in my code or in VS.NET2003 C++ compiler

James Brown6-Oct-05 21:56

James Brown

6-Oct-05 21:56

When you invalidate a rectangle/region, this area does not get updated straight away. It will get updated the next time Windows decides to send your app a WM_PAINT message.

To force an update after you invalidate a region, call the UpdateWindow API

James

http://www.catch22.net

MFC DLL question

benjnp6-Oct-05 14:57

benjnp

6-Oct-05 14:57

can an MFC DLL server created in VC be used by a VB client? because most articles that i read that allows VB client are ATL and win32 dlls.

Re: MFC DLL question

Prakash Nadar6-Oct-05 15:44

Prakash Nadar

6-Oct-05 15:44

if you are talking about ATL com, yes.

Then you need to take care of data been exchanged between VB and COM.

I dont remember where, but somewhere I have read on how to write a COM object in VC for VB.

-prakash

Objects

kenexcelon6-Oct-05 14:10

kenexcelon

6-Oct-05 14:10

I'm having to develop an application that keeps track of horses with their winnings and other such information dealing with horse races. We only have to track 3 horses, but what if there were 100 horses, which it'll have to do eventually? I don't want to have to type HorseName.ShowStatistics that many times. Is there a way to loop through the horse objects and run that specific objects method within the loop? How would I go about doing that?

Thanks

Re: Objects

Prakash Nadar6-Oct-05 15:40

Prakash Nadar

6-Oct-05 15:40

Horses oHorses[100];

or Horses *pHoress = new Horses[100]

<<Initialise the horses members>>

for(i=0;i<100;i++)
{
pHorses[i]->ShowStat();
}

-prakash

-- modified at 21:41 Thursday 6th October, 2005

Re: Objects

Cedric Moonen6-Oct-05 20:39

Cedric Moonen

6-Oct-05 20:39

To complete previous response, you can use the vector from the STL. This will allow you to have an array of objects (Horses in your case) where you can dynamically add and remove elements.

Zhaohui Xing (Joey)6-Oct-05 11:40

Zhaohui Xing (Joey)

6-Oct-05 11:40

I compile the following C++ code VS.NET2003 IDE and the compiler enter an infinit/endless compiling process, What's wrong within it?
The code is given as following:
//The testtempl.h
#ifndef __TESTTEMPL_H__
#define __TESTTEMPL_H__

#include <stdlib.h>
#include <stdio.h>
#include <vector>

template<int n> class MyTempl
{
public:
std::vector<int> m_array;

public:
MyTempl()
{
m_array.assign(n, n);
}

int Summation()
{
int rn = 0;

for(int i = 0; i < (int)m_array.size(); i++)
rn += m_array[i];

return rn;
}

int Foo()
{
if(n <= 1)
return 1;
else
{
int r = 0;

MyTempl<n-1> mtempl;
r = mtempl.Foo()*Summation();
return r;
}
}
};

typedef MyTempl<4> My4Foo;

#endif

//The testtempl.cpp file
#include "testtempl.h"

int main(int argc, char* argv[])
{
My4Foo myfoo;

int i = myfoo.Foo();

printf("foo value: %u\n", i);

return 0;
}

-- modified at 19:25 Thursday 6th October, 2005

Re: What's wrong in my code or in VS.NET2003 C++ compiler

Christian Graus6-Oct-05 12:41

Christian Graus

6-Oct-05 12:41

First of all, check 'do not treat < as html' below, so we can SEE the code

I think this line

MyTempl<n-1> mtempl;

means that every time the compiler creates a template class, it needs to create a new one, recursively forever. Hence the error.

Christian Graus - Microsoft MVP - C++

-- modified at 18:51 Thursday 6th October, 2005

Re: What's wrong in my code or in VS.NET2003 C++ compiler

Jose Lamas Rios6-Oct-05 18:55